This invention relates generally to a method of reducing barre in synthetic polyamide textiles dyed with acid dyes. More particularly it relates to a method of dyeing synthetic polyamide textiles with acid dyes using as the principal dye leveler a synergistic mixture of a particular alkyl sulfonate surfactant and a particular alkyl aryl sulfonate surfactant.
In dyeing synthetic polyamide textiles such as fibers, fabrics or garments (hereafter collectively called "nylon" or "nylon textiles") with acid dyes, there often is obtained barre or streakiness in the dyed textile due to inherent physical and/or chemical differences existing in the yarns from which the textile has been made. For further information about the causes and manifestations of barre reference is made to U.S. Pat. No. 3,619,122 and American Dyestuff Reporter, Feb. 12, 1968, pgs. 42-47.
To prevent or minimize barre to an acceptable degree, a variety of anionic surfactants have been employed as dyeing levelers in the dyeing of nylon textiles with acid dyes. One of the earliest class of anionic surfactants used were the mixed fatty alcohol sodium sulfates. Subsequently, alkyl sulfonate and alkyl diaryl sulfonate type surfactants were recommended. In recent times, more complex and costly anionics have been alleged in patents to prevent barre; e.g. sulfonated sulphones derived from a variety hydroxy-substituted aryl compounds in U.S. Pat. No. 3,536,438, dialkyl sulfosuccinates in U.S. Pat. No. 3,619,122, and alkane-or alkene-amido-benzene-sulphonics in U.S. Pat. No. 3,713,768.
In spite of the abundance of work done to identify anionic surfactants capable of minimizing or preventing barre, a need still exists for improved dyed levelers considering the great number of different acid dyes employed, the fact that they are typically used in combinations, and the variety of nylons textiles being dyed. In many instances less than satisfactory barre effects are tolerated because a dye leveler suitable from both an economic and a performance standpoint is unavailable.